1. Field of the Invention
The present invention relates to video-on-demand (VOD) services, and more particularly, to a method and system for providing VOD services in a digital cable TV network.
2. Description of the Related Art
Video-on-demand (VOD) services provide video data, such as a movie or news, via a network at the request of a subscriber. In general, a VOD service is realized by compressing a video program using a digital data compression method such as MPEG-2, storing the compressed video program in a VOD server, and providing the stored video program to a subscriber via an Internet protocol (IP) network or a digital cable TV network when the subscriber requests the corresponding video program.
Korean Laid-Open Patent Gazette No. 2002-0090727 discloses a set-top box network system that can download a broadcast program and provide a VOD service using an IP network. However, broadband networks do not have sufficient bandwidth to provide high-quality VOD services even though they were commercialized for a long time. Therefore, the quality of many Internet VOD services is generally lower than the quality of TV broadcast programs.
Korean Laid-Open Patent Gazette No. 1996-0706749 (International Patent Application No. WO 1995/015658) discloses a network manager for a cable TV system head end that is useful for processing upstream subscriber communications and can provide various services, such as near VOD services, virtual VOD services, and interactive program services. However, there is still uncertainty regarding how the network manager is able to search for a subscriber in a cable TV network, recognize a set-top box of the subscriber, and provide a tailor-made VOD service to the subscriber. In other words, the network manager can provide VOD services to a subscriber if a VOD server is connected to the subscriber's set-top box. However, since received VOD channels may differ depending on the service network, the network manager may not be able to determine to which set-top box in which cell it should transmit a program.
Recently, digital cable TV networks provide out-of-band channels, which can be used for data transmissions, as well as in-band channels, via which broadcast programs are provided. These out-of-band channels have made interactive TV broadcasting and unidirectional TV broadcasting possible, a conventional way of broadcasting in which broadcast programs are transmitted only in one direction. In addition, subscribers can enjoy point-to-point communications using their set-top boxes. Accordingly, VOD services can be easily implemented on a digital cable TV network. Unlike in-band channels, however, out-of-band channels do not have the necessary bandwidth to provide high-quality VOD services.
Therefore, in order to satisfy the demands of both subscribers and content providers, it is necessary to develop a system and method for TV network that enables point-to-point communication and has sufficient bandwidth to provide high quality VOD services in a digital cable network.